But emissions are likely to increase as the economy recovers, highlighting the challenge in cutting carbon in areas such as transport and housing to meet the goal to end the UK’s contribution to climate change by 2050.
The assessment by climate and energy website Carbon Brief estimates that UK greenhouse gases fell by 11% in 2020, the biggest annual fall in at least 30 years and a bigger drop than after the global financial crisis in 2009.
The significant reduction in 2020 means the UK has seen emissions fall 51% since 1990, the benchmark year for measuring greenhouse gas reductions under laws to tackle the climate crisis.
The law requires the UK to cut greenhouse gases to net zero by 2050 – a 100% reduction on 1990 levels – by reducing emissions as much as possible and taking steps such as planting trees to offset any remaining pollution.
Last year marked the halfway point in the 60-year period to achieve net zero, and the analysis showed emissions were down more than half, from 794 million tonnes of greenhouse gases in 1990 to 389 million tonnes in 2020.
But last year’s falls, which helped push UK emission cuts past the halfway point, were largely the result of lockdown reducing car use and gas-powered electricity, as well as warmer weather that cut heating demand, analysts said.
Emissions will likely rise again in 2021 or 2022 as the economy recovers from the pandemic and people increasingly get back in their cars, Carbon Brief said.
In 2020 around 60% of the annual reduction came from lower oil use, mostly a reduction in petrol and diesel sales as lockdown took hold, costing the Treasury around £5 billion in lost fuel duty revenues, the analysis said.
While there may be an increase in home working after restrictions are lifted, that could be offset by nervousness over using public transport which encourages people to drive.
And while electric vehicle sales now make up more than 10% of new cars, they only account for 1% of cars on the road, with a negligible impact on transport emissions which have dropped little in the 30 years since 1990.
But the analysis also shows that the UK’s power sector has transformed in 30 years.
In 1990, two-thirds of electricity came from coal, 10% from oil and just 2% from renewables, but by 2020 the UK was generating more power from wind, solar, biomass and hydro than fossil fuels in 2020, with nearly half of days coal-free.
Industry has also cleaned up its act, with controls on landfill methane and other greenhouse gases, and more efficient industrial processes, as well as a structural shift away from carbon-intensive manufacturing.
There is also a smaller and cleaner fossil fuel supply industry with lower emissions from coal mines and leaky gas distribution pipes, Carbon Brief said.
Emissions of carbon dioxide, which makes up the lion’s share of greenhouse gas pollution, are now at their lowest level since 1879, the analysis shows.
Per person, UK greenhouse gas emissions are now as low as they were in 1853, and are roughly in line with the global average, making them lower than for each person in the US or China though still three times that of India.
Greenpeace UK’s head of climate Kate Blagojevic warned the findings were not a cause for celebration as the UK was still a long way from reaching its climate commitments.
She said: “Make no mistake, the scale of necessary future emission cuts are far greater than anything that has been managed during the pandemic.
“We need much more Government funding, policies and political will to cut emissions from our homes, cars, industry and agriculture if we are to meet our climate targets once normal life resumes.”
Carbon Brief’s estimates of the UK’s greenhouse gas emissions in 2020 are based on analysis of provisional energy use figures published by the Business Department (Beis) last month.
They cover domestic emissions but not those associated with imported goods or international aviation or shipping.